Audio devices include for example hearing aids, loudspeaker units for a hearing aid or a headset or the like. Hearing aids can be characterized by the way they are fitted to the ear of a user. Conventional hearing aids include for example ITE (In-The-Ear), ITC (In-The-Canal), CIC (Completely-In-the-Canal) and BTE (Behind-The-Ear) hearing aids. The components of the ITE hearing aids are mainly located in an ear, while ITC and CIC hearing aid components are located in an ear canal. BTE hearing aids are generally mounted behind or on an ear of a user. The hearing aids all have at least a microphone, a power source, electric circuitry and a receiver (speaker). The receiver generates sound, which can be guided to a tympanic membrane in the ear canal of a user for auditory perception. Therefore all hearing aids have at least one insertion part, which is adapted to be inserted into an ear canal of a user to guide the sound to a tympanic membrane. The insertion part can for example be a loudspeaker unit for a hearing aid or a headset.
Inserting an insertion part of an audio device into an ear canal that transmits device generated sound into the ear canal can lead to various acoustic effects, e.g., a comb filter effect, sound oscillations or occlusion. Simultaneous occurrence of device generated and natural sound in an ear canal of a user creates the comb filter effect, as the sounds reach the tympanic membrane with a time delay. Sound oscillations generally occur only for audio devices including a microphone, with the sound oscillations being generated through sound reflections off the ear canal to the microphone of the audio device. A common way to suppress the aforementioned acoustic effects is to close the ear canal, which effectively prevents natural sound to reach the tympanic membrane and device generated sound to leave the ear canal. Closing the ear canal, however, leads to the occlusion effect, which corresponds to an amplification of a person's own voice when the ear canal is closed, as bone-conducted sound vibrations cannot escape through the ear canal and reverberate off the insertion part of the audio device. To reduce the occlusion the insertion part of the audio device can be inserted deeper into the ear canal to adhere to a bony portion of the ear canal and to seal the ear canal.
To seal the bony portion of an ear canal with the insertion part of the audio device often a moisture-activated adhesive is applied on the outside surface of the insertion part, e. g., a loudspeaker unit. The adhesive has to be pressed against the skin of the ear canal to ensure a reliable adhesion to the skin. The skin in the bony portion of an ear canal is sensitive to pressure and the required pressure applied to the skin often causes pain, skin irritations and wounds in the ear canal.
U.S. Pat. No. 7,141,014 B2 shows a cushioning device for use with a hearing aid instrument for positioning of the hearing aid instrument in the ear of a user. The cushioning device comprises a ring volume with a pliant substance disposed within the ring volume and a reservoir, which are in fluid communication. The ring volume encircles a predetermined portion of a hearing aid housing configured to generally conform to the shape of the ear canal and separates it from a portion of a user's ear canal. The hearing aid housing contains the electronic of the hearing aid instrument. A pressure of the pliant substance can be increased or decreased by closing or opening a door movably disposed at an end of the hearing aid instrument opposite the ring volume.
U.S. Pat. No. 6,094,494 presents a device and method for fitting a sound transmission device with an ear-piece component comprising a housing having a face at one end with operative components and a stem adjacent the other end. The stem houses a speaker tube and retaining means for securing an inflatable, resilient fitting balloon. The component and attached fitting balloon are inserted into the ear canal when the balloon is in a deflated configuration. The fitting balloon is inflated through air supply through an air channel of the stem housing when the balloon is in the ear canal, which engages the ear-piece component against the walls and prevents sound from entering and escaping the ear.
In WO 2010/136457 A1 an ear fitting piece for creating an ear impression and a method for creating an ear impression is presented. The ear fitting piece comprises a soft rubber sleeve enclosing a liquid with a first state in which it can be shaped and a second state in which it is solidified and an activating means, which is designed to cause a change of state from the first to the second state of the liquid. A change from the second state to the first state of the liquid can be caused by heating.
WO 2007/146934 A2 presents a seal for retaining a hearing device within a portion of the ear canal. The seal comprises a curved compliant shell with a wall and an opening at an apex portion of the shell. The shell wall defines a cavity for retention of a hearing device component. A portion of the shell comprises a resilient material with sound attenuating properties. The structure of the shell allows a force for removal of the seal from the ear canal to be greater than a force for the insertion of the seal into the canal. The seal can be configured to be seated in a bony portion of the ear canal. A coating that enhances adhesion between the seal and the canal can be applied on the seal to facilitate retention in the ear canal. The seal can be of biocompatible materials and can further be configured to exert a force on the epithelium less than the venous return pressure of the epithelial vasculature.
The disclosure provides an an improved audio device for insertion into the bony portion of the ear canal.